A lamp is put into a fixture to produce light. Miniature bulbs or lamps are by definition generally small in size and used, for example, for task or indicator lighting. The bulb described here is one for an otoscope or opthalmoscope.
An otoscope is an instrument used in the medical field to examine the external ear, the eardrum, and, through the eardrum, the ossicles of the middle ear. An opthalmoscope is a device used in the medical field to examine the eye. Both units can share the same basic concepts as follows. The scope can consist of a light and/or a magnifying lens. A scope can have a gripping body and a top attachment to shine light into a patient's ear or eye. The top attachment can be connected to a top end of the gripping body, and in some versions a viewing port can be connected to the top end of the gripping body, which itself can contain a battery compartment, to provide a line of sight through the ear speculum. A scope can also include a light source that is directed through the ear speculum. The disclosures of the present invention are directed in particular to this light source, as well as light sources used in many other industries, tools, instruments, and appliances. The majority of the above features are described, for example, in U.S. Pat. No. 3,698,387 to Moore et al., and as further illustrated in FIG. 1, which is a figure from U.S. Pat. No. 3,698,387 to Moore et al., the contents of which is incorporated by reference in its entirety.
Instruments, such as the devices described above, require inefficient large light sources such as incandescent, halogen, or tungsten. They require such large light sources because their collection and delivery of light design is inefficient. These large light sources use a great amount of electrical power that drains the small battery in these small devices quickly. Typically the traditional bulbs used in these applications have light illuminated in a very specific (usually omni-directional) manner, which is difficult to focus into a tight beam.
The light source used in the Welch-Allyn otoscope, for example, consists of a tungsten filament miniature lamp mounted on top of a removable hollow cylindrical metal piece as shown in FIG. 2. This lamp is powered by a rechargeable battery incased within the gripping body of the scope. The lamp makes electrical contact to the battery at the base of the cylindrical metal through an electrical insulated metal rod (anode) and through the outer metal cylinder (cathode). The lamp is turned on-off with the scope's switch that makes electrical contact at the outer wall of the metal hollow cylinder of the lamp. The lamp intensity is also dimmable via a resistor built into the switch. Some of the drawbacks of halogen bulbs are that they burn very hot and eagerly consume battery power, which causes the need to frequently recharge the lamps. They are also very fragile and easily damaged.
An alternative of this light source, as discovered as part of the present invention, is an LED light source as described in the present invention. One advantage of the present LED light source over halogen (incandescent) light sources is that the LED bulb contains no fragile filament that can be easily damaged and/or burned out over time. The LED light source of the present invention lasts more than 50,000 hours, essentially forever, and will not be damaged by rough handling, dropping, or sudden movement.
While at least one LED otoscope exists, it has a number of shortcomings. One embodiment of a LED otoscope is described in United States Patent Application Publication No. 2004/0186352 by Roberts et al., and as further illustrated in FIG. 3, which is a figure from United States Patent Application Publication No. 2004/0186352 by Roberts et al., the contents of which is incorporated by reference in its entirety. A major disadvantage to the LED otoscope described by Roberts is the resistance within the medical industry to change their existing devices. For example, Welch-Allyn is a trusted name in medical lighting instruments. The majority of medical personnel and facilities use Welch-Allyn devices which they have owned for many years. The device is trusted and therefore the medical personnel or facility has no desire to switch to a completely new device where the reliability is greatly unknown. The disclosures of the present invention allow for the light sources of the present invention to easily replace existing light sources, thereby allowing for easy retrofitting.
When an LED is going to be used in an application which has restrained physical space, thermal management is extremely important. A LED should be mounted to a heat sink with sufficient ability to pull heat away from the LED die without it reaching critical maximum temperatures. Most prior heat sinks require the use of wires, plastic, or other materials in order to electrically insulate the anode and cathode of the LED while connecting the anode and cathode to the power source. Any prior heat sink would suffer thermally from the use of materials which are not good thermal conductors.